The present invention relates to hose clamps for attaching elastomeric hoses to a conduit, such as a pipe.
Hose clamps are known which encircle the hose, and are contracted, as by a screw or bolt, to cause the diameter to diminish, and thereby clamp the hose onto a pipe. Those hose clamps comprise two parallel encircling wires, typically made of a single bent and formed length of wire. The hose clamp includes a nut for engagement by the screw, and the screw has a head which may be engaged by a suitable tool, such as a screwdriver or wrench, to rotate the screw and thereby tighten the clamp. Examples of hose clamps of the foregoing construction are Embree, U.S. Pat. No. 1,815,145, Heuer, U.S. Pat. No. 1,947,715, McLaughlin, U.S. Pat. No. 2,002,671 and Murray, U.S. Pat. No. 2,536,612.
Such hose clamps are applied to hoses by moving them axially over the ends of the hoses, where they are initially tightened to secure them to the hose, and subsequently further tightened in order to compress the hoses, which are of elastomeric material, and thereby clamp the hose onto the pipe in a leak-proof manner. The two steps may be done in close, substantially inseparable sequences, or the two steps may be performed as a first step of attaching the clamp to the hose, after which the hose and clamp are transported, and then the hose with the attached clamp is associated with the pipe and the hose clamp is then clamped onto the pipe in a second step.
It has been found that when the hose clamp is in position on the hose, and with the hose placed on a pipe, when the head of the screw is engaged by a tool, such as a screwdriver or a wrench, the force applied to the screw head has two components: a torque to rotate the screw, and a force along the axis of the screw, which tends to rotate the clamp on the hose, thus moving the entire clamp, including the screw head, to a different circumferential position, where it is less accessible to the tool. This situation has required either the holding of the clamp and the hose by the workman, requiring a somewhat cumbersome operation, or if the hose clamp is permitted to rotate, either the tool must be repositioned, or the clamp rotated back to its original position, to provide ready access to the head of the screw.
At the present time, and for many years passed, it has been the practice to pre-assemble the clamp onto the hose, and to provide the workman with a hose of the prescribed length for assembly to the pipes to which the hose is to be attached. A widely used technique is to attach the hose clamp, preferably of the encircling wire type hereinabove discussed, to the hose by a staple which engages the clamp and which penetrates into and through the hose. The hose being thus penetrated is subject to leaking. The problems provided by the stapling of the encircling wire hose clamp onto the hose have been known for many years. For example, Tetzlaff et al. U.S. Pat. No. 3,454,996 discloses the problems resulting from the stapled-on wire hose clamp, and provides a proposed solution which includes an additional band associated with the wire hose clamp, and having prongs extending from the band over the end of the hose, and then penetrating the hose near its end, extending from the inside of the hose radially outwardly. The construction including the band provides an anchor or locating apparatus for the wire hose clamp, but requires the expense of an extra element of the wire hose clamp, and also requires the manipulation of the prongs, to effect penetration of the hose.
There are known in the prior art a number of radially contractible hose clamps which have radially extending spurs or the like extending from the inner surface of them. For example, Hecox, U.S. Pat. No. 386,882 provides a hose clamp in the form of a metal band having spurs which extend radially, and engage or prick into the hose upon operation of a lever. Tunstall et al., U.S. Pat. No. 3,422,469 has serrations or teeth which extend radially inwardly and serve to grip and engage a metal coupling on the hose. Taylor, U.S. Pat. No. 3,231,955 provides a device in the form of a handle which is attached to a nozzle, apparently of metal, so as to rotate it and cause it to thread onto the threads of a faucet; the handle is in the form of an annular element with inwardly directed teeth to engage the nozzle, and a pair of radially extending handle parts. In these constructions, the radially extending teeth or ribs were not inclined so as to be set into anchoring position by a force on the clamp tending to rotate it, nor were they inclined so as to permit easy and ready assembly onto the end of a hose.